The present invention relates in general to a handheld test device for analyzing a body fluid and in particular to a portable blood sugar measuring device having a tape unit for advancing a test tape in sections, a detection unit for recording measured values on the test tape sections to which body fluid has been applied in the area of a receiving position, and a housing for holding the tape unit and detection unit.
Regular blood sugar monitoring is essential for diabetics because their treatment, diet and rhythm of life must often be adjusted based upon their monitored glucose levels. Handheld instruments that operate as “mini-laboratories” are widely available for self-monitoring and allow the necessary steps to be carried out simply and rapidly, even by laymen. Typically, disposable test strips are provided that are inserted into the instrument for determining glucose level, for example, by an optical measuring unit after the test strip is dosed with capillary blood. However, the storage and processing of these test strips require a large amount of space and also require complicated drives.
EP Applications No. 02026242.4 and 02028894.0 propose that a wound test tape on which a plurality of test sections provided with a suitable test chemistry are arranged consecutively should be used instead of individual test strips. The body fluid is applied and analyzed on a test section that is moved into an active position by advancing the tape. These patent applications give details about blood collection and also on the known test media and detection systems, especially for blood glucose, to which reference is herewith made and the content thereof is incorporated into this application.
In order to exactly dose the smallest possible amounts of blood, it has been proposed to expose the test tape over a deflection head external to the housing. A problem with this approach is protecting the complicated and sensitive measuring arrangement against external influences and to exactly align the detection optics.